The function of the foot during walking is that of balance and support with forward locomotion maintained by the lower extremities and momentum of the upper body. The foot acts as a mobile adaptor to the ground at heel stroke and early stance phase and then stabilizes to function in propulsion of push-off. Body weight is accepted into the foot at heel strike and transferred anteriorly during foot flat and push-off. The heel first contacts the ground in an inverted position. The adaptation of the foot to the ground occurs by eversion of the calcaneus and pronation of the subtalar and midtarsal joints. The medial longitudinal arch undergoes structural change during early stance phase by accepting weight from the talas as it assumes a plantarflexed and adducted position. At midstance, external rotation of the lower extremity initiates supination of the foot. The calcaneus inverts and the talas moves into abduction and dorsiflexion, thereby locking the midtarsal joint, allowing the foot to become more rigid during push-off. Supination is further assisted by the oblique axis between the second and fifth metatarsals which causes the midfoot to supinate passively as weight is shifted onto the metatarsals. The foot also becomes more stable at push-off due to the windlass mechanism of the plantar fascia and the activity of the gastrocsoleus muscle group. During walking, the ground reaction forces in each foot segment varies during different phases of the gait cycle. Weight distribution moves through a line of central pressure. Generally, the center of pressure begins at the lateral heel, moves forward into the midfoot, and then shifts medially where it exits between the first and second toes at push-off. At push-off all of the ground reaction forces are concentrated on the metatarsus and toes. Substantial forces are transferred to the heel, ball and toe of each foot during walking, jogging and running activities. These biomechanics of the foot are reviewed by Gordon E. Doxey in the Journal of Orthopedic and Sports Therapy May/June 1985 Pages 324-333.